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#1001 Re: Help Me ! » Fibonacci Sequence » 2006-11-15 15:03:06

Ricky, 2 should replace 2[sup]n[/sup] in your formula

#1002 Re: Dark Discussions at Cafe Infinity » Playing guitar on YouTube » 2006-11-14 22:11:07

They sent me two e-mails, none of which mentions the prize I've won. sad

#1003 Re: Help Me ! » Help~ Don't know how to do these...please show me how... » 2006-11-14 22:02:39

Simple solution:
The pavement and the pool altogether form a larger rectangular, (12+2x)m by (6+2x)m.
So the area of the pavement is:
(12+2x) (6+2x) - 12 6 = 24x+12x+4x²= 36x+4x² (m²)
To solve the x, use the identity of the pool area:
36x+4x² (m²)=7/8 12 6

The answer to Q2:
120 Pi = x Pi((x+2)²-x²)
You can solve Pi now

#1004 Re: Maths Teaching Resources » Advanced Linear Algebra » 2006-11-14 13:18:28

It's nice to have so many free books today. Thank you Ricky. smile

#1007 Re: Dark Discussions at Cafe Infinity » Playing guitar on YouTube » 2006-11-14 12:57:47

Thank you very much! Your page has announced me as the 999,999,999th visitor on youtube and FreeLotto granted me 2,087 dollars as prize!
Don't know how much I can get after tax though~

#1008 Re: Help Me ! » Oh noes not another geometry problem » 2006-11-14 02:38:57

First, I would suggest you to solve x out using the identity VQ=VW+WQ
Then, you can draw RB vertical to TU and PS with intersection A and B. I think you can work it out now.

#1009 Re: Help Me ! » Power test » 2006-11-13 17:51:02

b is more powerful, definately.
But without the Standard Deviation around 1%, none could do such a test.

#1010 Re: Dark Discussions at Cafe Infinity » free will is a falacy » 2006-11-13 17:46:46

Okay, I admit I have a causality preassumption in my mind.
I don't believe:
A change could happen out of the constant.

I believe it should have been caused, either externally or internally.

#1011 Re: Dark Discussions at Cafe Infinity » free will is a falacy » 2006-11-12 15:05:16

About the change:

If the change cannot be caused by exterior things, like common causality we assume,
it should have been attributed to itself-Hegal's Philosophy.

Hegal pointed out that a thing naturally changes itself because of the interaction between its components.

#1012 Re: Puzzles and Games » Swimming with Sharks » 2006-11-11 23:43:32

Game theory.
I would rather see the game as a mimic of two competing firms at the point to decide whether or not to invest in R&D unprotected. And this makes it less cruel.

#1013 Re: Dark Discussions at Cafe Infinity » free will is a falacy » 2006-11-11 16:07:56

I think what luca meant by "illogical" is that why does an event simply happen? How can it occur rather than not? Why doesn't everything stay the same and hence nothing new occurs?

Despite that we sometimes, most of the times perhaps, fail to point of what have cause it to occur, we still assume that it occurs under some reasons, and that a difference like this event must have been caused by something changed prior to its occurance, so long as we don't believe in some god scheduling it. Thus this inference is somhow within the framework of atheism, for if you assume everything is arranged by a god, there is no value to ask its material cause, which is just the extreme of doomism. Most people, however, choose some middle between atheism and doomism.

Ancient Greek philosophiers had studied atheism so far that Aristotle had reached a milestone. He argued that everything has a purpose-maybe many purposes in today's view- dominating its occurance, its development, its peak, and its deceasing, then the thing itself becoming another purpose. Naturally, there must be an original purpose to start all this, and he named it the ethos.

#1014 Re: Help Me ! » eleminating inverse for recursive least square » 2006-11-10 17:15:49

You don't have to
You can point out A'A= (A'A)'
and (A'A)[sup]-1[/sup]= [(A'A)[sup]-1[/sup]]',
which  need each theorems to prove.
In addition, there is no way to eliminate (A' A)^(-1) generally, and the final formula involves it.

#1016 Re: Help Me ! » Figuring out sin/cos/tan angel without calculator » 2006-11-08 14:24:08

I have one way to figure them out without a calculator. But you need other tools.
Find a piece of hard-paper, draw a circle with radius of integer centimetres, and cut. Also depict the co-ords cross with pen. Next time you wanna figure out a sin, just measure it from the round paper you carry with an angle-measure and a ruler. Sure you can improve the special tool, too. You can paste co-ords paper onto it so you may not need a ruler, and you can draw 10°, 20°,... on to it so that you no longer need to carry the tool to measure the angle if you are not that exact about the result.

#1017 Re: Help Me ! » To the power of 0 » 2006-11-07 14:04:56

Ricky wrote:
George,Y wrote:

Nice challenge.
Typically they would argue
0.1/0.1=1
0.01/0.01=1
0.001/0.001=1
......
Hence 0/0 could be defined as 1 when in the function x/x.

But I find this reason tricky and would refuse it.

That is a good reason, believe it or not, with the wrong conclusion.  But you have to make it a good reason first.  And to make it a good reason you do the following:

0.2/0.1 = 2
0.02 / 0.01 = 2
0.002/0.001= 2
......

Hence, we have arrived at two different ways to define 0/0, and thus, we say it is indeterminate.  And we could see from this pattern that we can make f(x) / g(x) approach 0/0, but equal any real number we wish.

I have said when in the function x/x, haven't I?

#1018 Re: Help Me ! » Is this true?? » 2006-11-07 14:03:35

Ricky wrote:

And sorry I don't quite agree with the so-called rules designed to cover a bunch of paradoxies created by the original concept.

Paradox?  I'm sorry, but what paradox?  The only thing you have said so far is that stating .999... = 1 requires a guess.

Great point, since you finally keep it in mind. I'll explore the other paradoxes soon. Wait for me

#1019 Re: Introductions » Hi! » 2006-11-06 15:46:31

Devanté wrote:

If you have a mouse with a wheel on it, hold down [Ctrl] and spin the wheel towards you to make the page bigger. Spin it the other way to make it smaller. smile

This way always fails when you want them bigger, due to the framework embeding letters dunno

#1020 Re: Help Me ! » Help Please! » 2006-11-06 15:33:36

as categorily distributed as in the population.
For example, male:female=100:105
kids:whole=1/10 or something.
And, sufficiantly large sample, better at least 35 for each category, so your overall data might contain hundreds of samples.

#1021 Re: Help Me ! » Is this true?? » 2006-11-06 15:28:04

And the proof does imply ∞+1=∞ regarding how "many" "9"s

#1022 Re: Help Me ! » To the power of 0 » 2006-11-06 15:25:53

Nice challenge.
Typically they would argue
0.1/0.1=1
0.01/0.01=1
0.001/0.001=1
......
Hence 0/0 could be defined as 1 when in the function x/x.

But I find this reason tricky and would refuse it.

#1023 Re: Help Me ! » Is this true?? » 2006-11-06 15:18:22

I do wanna argue that the approach of 10*0.999... thing does imply the last "9" equals the second last "9". And sorry I don't quite agree with the so-called rules designed to cover a bunch of paradoxies created by the original concept.

#1024 Re: Help Me ! » A reversal of the Birthday Problem » 2006-11-06 15:12:44

most of whom aren't experts in statistics and none of whom have probably have read the papers you're referring to.
-he he, you are right.

However, this time I have been patient, and I think s-c you probably made the problem too complicated.

First, forget about birthday and life-span. Let's say a person could die at any date of any year. And generally, he/she has the same chance, or almost the same chance to die on some Jan 1st , some July 1st or some Dec 31st. In the same year the date may represent some different life-spans, but they may represent another different ones in different years.

Hence the problem could be simplier. Count how many significant days in a year, and how-many/365.25 would be the general frequency of significant days across the history, then mutiply each relative's how-many/365.25 to represent they all die on some significant day.

#1025 Re: Introductions » Hi! » 2006-11-05 20:30:53

Letter Size TOO Small, better Bigger

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